Indicating device



R. F. HUNTLEY INDICATING DEVICE Filed March 16, 1962 INVENTOR.

BY da,

Hunieg United States Patent O Delaware Filed Mai'. 16, 1962, Ser. No.180,094 3 Claims. (Cl. 116-124.1)

This invention is directed to indicating devices and more specifically,to an indicating device for a wave-signal receiver tuning mechanism.

In the past, pocket size transistorized radios have largely providedinadequate indicating means for the tuner of the radio. The legend ornumbers indicating station frequencies have usually been spaced on theperiphery of the tuning knob which normally has a rotational limitationof 180. Therefore, the station numbers have to be spaced quite closelywhich makes tuning very critical and difficult for the average user. Theuse of a Venier type of tuning knob reduces the criticality of tuningbut is an added expense and, in any event, the close spacing ofthefrequency indicating numbers still makes visual tuning difficult. Sliderule dial scales are in general use on larger size radios but haveheretofore been impractical for the pocket size transistorized radiosbecause of cost and the large amount of space required.

Accordingly, it is a yprincipal object of this invention to provide animproved tuning indicator.

It is a more specific object of this invention to provide a tuningindicator having a slide rule dial scale for a radio of the pocket sizetransistor type.

It is yet another object of this invention to provide an indicatingdevice of the above type which is economical in construction andrequires a minimum amount of space.

In accordance with the above objects an indicating device for awave-signal receiver tuning mechanism is provided comprising a rotatableshaft movable with actuation of the tuning mechanism over a rangev whichis less than 360. A first lever is disposed transversely of the shaftand has one end affixed to the shaft and a second end which traces acircular arc upon rotation of the shaft over said range. A scale isprovided having a straight edge which constitutes a chord of the arc. Amovable indicator is mounted in camming engagement with this straightedge. A second lever has one end coupled to the indicator and anotherend pivotally coupled to the second end of the first lever. Spring meansare provided which bias the indicator against the straight edge.

The features of the present invention which are believed to be novel areset forth with particularity in the appended claims. The invention,together with further objects and advantages thereof, may best beunderstood by reference to the following description taken in connectionwith the accompanying drawing, in the several figures of which likereference numerals identify like elements, and in which:

FIGURE l is an elevational view of a pocket size transistorized radioembodying the present invention;

' FIGURE 2 shows an enlarged portion of FIGURE 1 partially cut away andpartially in section showing in detail the indicating device of thesubject invention; and

FIGURE 3 is a partial sectional view taken along line 3-3 of FIGURE 2.

The pocket radio of FIGURE 1 includes a cabinet 10 having a front panel11 composed of a lower portion 12 which serves as a speaker grille andan upper portion 15 which accommodates a slide rule dial scale assembly16. A speaker 13, shown in dashed outline, is positioned within cabinet10 behind grille 12.

Extending from the top of cabinet 10 are serratededges of two disks 17and 18 which may be actuated by the user of the radio. Disk 17 iscoupled to the on-oif volume Patented June 2, 1964 control and disk 18is coupled to the tuning mechanism and the remaining components andcircuitry of the receiver, except for its tuning indicator, are entirelystandard and will not be discussed in detail.

Referring now to FIGURE 3, which shows a portion of the tuning mechanismof the radio, disk 18 is fixed at its center to a rotatable tuning shaft20. Shaft 20, in turn, is coupled to movable tuning plates 21 which inconjunction with fixed plates 22 constitute a capacitor whosecapacitance varies with the rotation of shaft 20 to tune the radio to aselected frequency in a manner well `known in the art. The capacitorplates are arranged to limit the rotational range of shaft'20 to 180.

Dial scale 16 includes a straight edge 23 as shown in FIGURES 1-3 alongwhich a circular indicator 24 is mounted for sliding movement. The lowerportion of panel 11 forms an off-set 25 at its top, as best shown inFIGURE 3, to conceal all but a small sector of indicator 24, as bestshown in FIGURE 1. The position of this sector of the circular indicatorindicates the frequency to which the radio is tuned. In other words,indicator 24 may travel along scale 16 and its position may berread interms of frequency by reference to scale 16.

Indicator 24 is coupled to tuning shaft 20 by means of a two leverlinkage. The first lever may be considered as that portion of disk 18which, as best shown in FIG- URE 2, extends between shaft 20 and a stud26 fixed to an off-center point of the disk. In essence, one end of thelever is fixed to the tuning shaft and the second end constitutes theoff-center point. Stud 26 traces a circular arc of determined by thelimits of rotation of shaft 20, from a starting position indicated bythe full construction lines in FIGURE 2 where the tuning capacitor istuned to a high frequency corresponding to "16 on the dial scale and afinishing position shown by the dashed outline in which the tuningcapacitor is in its low frequency condition corresponding to 5.5 on theradio dial. Broken line 28 indicates the rotational range of stud 26between its starting and finishing positions.

Straight edge 23 of scale 16 is a chord of the arc through which stud 26travels and for an ideal mode of operation has a point 27 whichsubstantially coincides with the location of stud 26 in its finishingposition as shown in FIGURES 1 and 2.

Indicator 24 is coupled to stud 26 by a second lever 30 which has oneend 31 coupled to indicator 24 and another end 32 pivotally coupled tostud 26. FIGURE 2 showsY the two extreme positions of lever 30corresponding to the starting and finishing positions of stud 26.

Spring means are provided for biasing indicator 24- against straightedge 23 and include a spring 33 coiled around and fulcrumed on stud 26.Spring 33 includes two ends 34 and 35 which are held apart against thebias of the spring coils. More specifically, end 34 abuts against a hub36 on disk 18 and end 35 is hooked around an edge of lever 30 to biasthe lever and indicater 24 against straight edge 23. This bias ismaintained throughout the 180 rotation of disk 18. i

Operation Rotation of disk 18 by the user rotates tuning shaft 20 and atthe same time, through lever linkages 30 and the portion of disk 18connecting shaft 20 and stud 26, moves indicator 24 along straight edge23 to indicate the selected operating frequency of the receiver. Optimumlength of slide rule dial 16 is achieved by providing that the straightedge 23 has a point along its edge which coincides with the finishingposition of stud 26. If straight edge 23 were to be placed close to theaxis of rotation of shaft 20, lever 30 would have to be reduced inlength and this would greatly reduce the useful length of dial 16thereby impairing its effectiveness. On the other hand,

if straight edge 23 were placed further away from shaft 20 so as not toconstitute itself a chord of the are traced by the path of stud 26,indicator 24 would approach a reversal of motion before reaching itsfinishing position which would bring the indicator back toward the rightend of the scale and make visual tuning at the left end of the dialimpossible. The specific point of reversal occurs when shaft 20, stud 26and indicator 24 all fall in the same line.

Therefore, the present invention provides an improved tuning indicatorwhich gives the user the advantages of an adequate slide rule dial scaleand at the same time is an inexpensive indicating device requiring aminimum amount of space.

While a particular embodiment of the invention has been shown anddescribed, it will be obvious to those skilled in the art that changesand modifications may be made Without departing from the invention inits-broader aspects, and, therefore, the aim in the appended claims isto cover all suchchanges and modifications as fall within the truespirit and scope of the invention.

I claim:

1. An indicating device' for a Wave-signal receiver tuning mechanismcomprising: Y

a rotatable shaft movable with actuationY of said tuning mechanism overa range which is less than 360;

a first lever disposed transversely of said shaft having one end fixedto said shaft and a secondend which traces a circular arc upon rotationof said shaft over said range;

a scale having a straight edge which constitutes a chord of said arc;

a movable indicator mounted in camming engagement with said straightedge;

a second lever having one end coupled to said indicator and another endpivotally coupled to said second end of said first lever;

and spring means biasing said indicator against said straight edge.

2. An indicating device for a wave-signal receiver tuning mechanismcomprising: y

a rotatable shaft movable with actuation of said tuning mechanism overalrange of approximately 180;

a rst fixed-length lever disposed transversely of said shaft having oneend fixed to said shaft and a second end which traces a circular arcupon rotation of said shaft from a starting position to a finishingposition at opposed points in said range;

a scale having a straight edge including a point which substantiallycoincides with the location of said second end of said first lever insaid finishing position;

a movable indicator mounted in camming engagement with said straightedge;

a second fixed-length lever having one end coupled to said indicator andthe second end pivotally coupled to said second end of said first lever;

and spring means biasing said indicator against said straight edge.

3. An indicating device for a Wave-signal receiver tuning mechanismcomprising:

a rotatable tuning shaft for actuating said tuning mechanisrn having arotational range of approximately a disk coaxially mounted on said shaftfor rotation therewith and having a-predetermined olf-center point whichtraces a circular arc upon rotation of the shaft from a startingposition toa finishing position at opposed ends of said range;

a scale having a straight edge which constitutes a chord of said arc andincluding a point which substantially coincides with the location ofsaid off-center point of said disk in said finishing position;

a movable indicator mounted in camming engagement with said straightedge;

a stud secured at said off-center point of said disk;

a fixed-lengthV lever having one end coupled to said indicator and asecond end rotatably journalled on said stud;

and a spring fulcrumed onv said stud for biasing said indicator againstsaid straight edge.

References Cited in the file of this patent UNITED STATES PATENTS2,190,059 Edwards Feb. 13, 1940

1. AN INDICATING DEVICE FOR A WAVE-SIGNAL RECEIVER TUNING MECHANISMCOMPRISING: A ROTATABLE SHAFT MOVABLE WITH ACTUATION OF SAID TUNINGMECHANISM OVER A RANGE WHICH IS LESS THAN 360*; A FIRST LEVER DISPOSEDTRANSVERSELY OF SAID SHAFT HAVING ONE END FIXED TO SAID SHAFT AND ASECOND END WHICH TRACES A CIRCULAR ARC UPON ROTATION OF SAID SHAFT OVERSAID RANGE; A SCALE HAVING A STRAIGHT EDGE WHICH CONSTITUTES A CHORD OFSAID ARC; A MOVABLE INDICATOR MOUNTED IN CAMMING ENGAGEMENT WITH SAIDSTRAIGHT EDGE; A SECOND LEVER HAVING ONE END COUPLED TO SAID INDICATORAND ANOTHER END PIVOTALLY COUPLED TO SAID SECOND END OF SAID FIRSTLEVER; AND SPRING MEANS BIASING SAID INDICATOR AGAINST SAID STRAIGHTEDGE.